Depolymerization of Turkish lignites. I. Effect of substituted phenols

A lignite (C, 67.4 wt%) was depolymerized with phenol, p-nitrophenol and o-chlorophenol using sulphuric acid as catalyst. The solubility of the lignite was enhanced by these treatments, with phenol being the most reactive reagent whereas p-nitrophenol was the least reactive. The distribution of nitro- and chloro-groups in the solubilized products was investigated by infrared spectrometry and it was found that these groups were redistributed among the pyridine- and methanol-soluble materials. It is suggested that benzene-soluble material is produced by self-depolymerization of coal or by degradation of pyridine- and methanol-soluble material.     

爽“朗”曲调 芬朗SP-6.5A两分频套装测试报告

正自2月在第十届AAITF展会上公布了今年陆续发售的众多全新产品后,笔者一直关注着芬朗公司的具体动向。本月中旬,笔者受邀前往广州车元素旗舰店测试芬朗Feelart推出不久的性价比型两分频套装喇叭——SP-6.5A。外观工艺简单介绍一下SP-6.5A的外观,其实从产品系列来讲,SP-6.5在芬朗的产品线中属于第三梯队的极速摇滚系列,该系列的产品定位是为满足车主在进入汽车音响改装之门后对音色声效     

Compatibilization of inorganic particles for polymeric nanocomposites. Optimization of the size and the compatibility of ZnO particles

Summary The synthesis of in-situ hydrophobic functionalized ZnO nanoparticles via an emulsion process is systematically investigated. Different parameters are varied, such as precursor salt concentration and ultrasonification, to optimize the size and the size distribution of the ZnO particles. Particles with a size below 25 nm and surrounded by a hydrophobic polymer shell can be easily obtained. The influence of the polymeric shell on the compatibility with different polymeric matrices is described. Due to the small size of the inorganic particles and the excellent hydrophobization, highly transparent inorganic/organic nanocomposites can be obtained by spin-coating and extrusion.     

Crystal structural refinement of the new compound TmAlB14

Single crystals of the new phase TmAlB₁₄ were grown using the high-temperature solution method. The crystal structure of TmAlB₁₄ was refined from X-ray powder diffraction data using the Rietveld method. The structure is of MgAlB₁₄-type with the space group Imma and unit cell parameters a = 5.8212(3) Å, B = 10.3837(2) Å and C = 8.1762(3) Å. The final, conventional R-valve and profile R-value are 0.031 and 0.064, respectively. The structure is characterized by a partial occupancy of both metal positions and a splitting of the thulium atomic position.     

Perceptually enhanced blind single-channel music source separation by Non-negative Matrix Factorization

We propose a new approach that improves perceptual quality of the separated sources in blind single-channel musical source separation. It uses the advantages of subspace learning based on Non-negative Matrix Factorization (NMF) in which the bases represent the notes. The cost function is formulated in the form of weighted β-divergence by adopting the PEAQ auditory model defined in ITU-R BS.1387 into the source separation. The proposed perceptually weighted factorization scheme is integrated into the Non-negative Matrix Factor 2-D Deconvolution (NMF2D) and Clustered Non-negative Matrix Factorization (CNMF) to overcome the source clustering problem encountered in under-determined source separation. It is shown that the introduced perceptually weighted NMF schemes, named as PW-NMF2D and PW-CNMF, efficiently learn the bases that enable us to apply a simple resynthesis of the musical sources based on the temporal model stored in the encoding matrix. Source separation performance has been reported on musical mixtures where 1–2 dB improvement is achieved in terms of SDR, SIR and SAR compared to the state-of-the-art methods. Performance has also been evaluated by perceptual measures resulting an improvement of 2–5 in OPS, TPS, IPS and APS values.     

Developments in micro-electron beam welding

At the ISF (Joining and Welding Institute, RWTH Aachen University) the long-established electron beam (EB) welding process is investigated to meet the requirements of the field of micro-applications. A modified LEO ZEISS DSM 962 scanning electron microscope (SEM) is being used as a Micro-EB welding machine. The diameter of the beam in welding mode is about 20 μm, with a maximum beam power of 6 Watt at 30 kV acceleration voltage. The process-specific advantages, such as the inertia-free movement of the tool electron beam, the very small beam diameter, the clean room environment which is due to processing in a vacuum (no shielding gas needed) and the excellent applicability for visual quality control offer the best preconditions for hybrid micro-assembly purposes. If the technology is down-scaled to a micro-level, physical effects occur whose consequences must be met with new approaches of solution. Joining of micro-components presupposes optimal contact conditions. If the micro-components are of a flexible type, those optimal conditions are difficult to implement. The ratio of forces during the joining process and also the low stiffness of the components which is due to the small dimensions require, on the one hand, the application of a suitable handling technique or, on the other hand, a specific beam manipulation strategy. Especially in the field of micro-applications, the possibility to exert influence on the thermal distortion by symmetrical heating and solidification processes is of particular importance. Therefore, the reproducibility of the welded joints is one of the great challenges in the field of microwelding. The investigations and developments done at the ISF show successful results in joining stainless steel sheet materials down to 30 μm thickness and steel wire down to 50 μm in diameter, whereas other materials (Tungsten, Aluminum, Titanium, Nickel) are under investigation.     

Quasi three-dimensional, n-bit optical memory based on the ellipsometric principle: model calculations

Model calculations on the ellipsometric memory are presented. The ellipsometric memory is an n-bit optical memory whose information is extracted by use of the ellipsometric principle. The memory cells of the device consist of thin-film multilayer structures, and the information of each memory cell is contained in the optical properties of the thin films. Several thin-film multilayer structures were examined in order to find out how different choices of layer materials and other system parameters such as layer thicknesses and wavelength affect resolutions and limitations of the ellipsometric memory. Such calculations are also useful for optimizing the readout resolution. It was found that it is possible to use memory cells having up to at least eight layers, which would permit 8-bit words to be stored at each location. It was also found that, in principle, several types of materials can be used as layer materials, and various aspects of different choices of materials are discussed.     

Hand and foot purpura ("glove and sock" syndrome) caused by parvovirus B19 infection

After a period of general nonspecific symptoms (weakness; nocturnal sweating) for a few days a 29-year-old man suddenly developed a purpura-like rash on both hands and feet ("glove and sock") with mild itching and oedema. A blood count demonstrated leukopenia (2100/microliters) with neutropenia (1100/microliters), thrombocytopenia (81,000/microliters) and reticulocytopenia (1/1000), while haemoglobin content was normal. The bone-marrow showed almost complete reduction of erythropoiesis with the presence of giant proerythroblasts. Granulopoiesis and megakaryopoiesis were unremarkable. Positive tests for IgM and IgG antibodies against parvovirus B19 established the diagnosis of infection with this organism. The rash, blood picture and bone-marrow changes all regressed spontaneously, without any treatment, within a week. The petechial or purpuric "glove and sock" syndrome may be a special form of parvovirus B19 infection.     

Mechanical theorem proving in projective geometry

We present an algorithm that is able to confirm projective incidence statements by carrying out calculations in the ring of all formal determinants (brackets) of a configuration. We will describe an implementation of this prover and present a series of examples treated by the prover, includingPappus' andDesargues' theorems, thesixteen point theorem, Saam's theorem, thebundle condition, theuniqueness of a harmonic point andPascal's theorem.